1. Field of the Invention
The present invention relates to a light source device for use in a medical apparatus such as an operation microscope, ophthalmoscope, or endoscope.
2. Description of Prior Art
The above-noted medical apparatus use a high luminance light source such as, for example, a halogen lamp for illuminating a part to be operated on, eye fundus under test, or internal part to be observed. Light from the light source is guided to the part or object to be illuminated simply through some transmission means such as, for example, an optical fiber, or further via an optical device for observation.
Halogen lamps used as the light source for such purposes have a relatively short lifetime and are likely to burn out during operation or observation. As a solution for such problem, a prior art is disclosed in U.S. Pat. No. 3,959,612. The device disclosed in this publication has an annular flange rotatably mounted in a lamp housing, and a plurality of halogen lamps mounted on the annular flange. Either one of the plurality of light sources can be selectively placed in an illuminating light path. The device further has a connector which can be electrically connected to the light source selectively placed in the illuminating light path.
If the light source placed in the illuminating light path burns out during operation or observation, the flange can be rotated to place another light source in the illuminating light path, the latter light source being then electrically connected to the connector and thus energized. Thus, interruption of the operation or observation can be avoided.
The prior art disclosed in the above-noted publication, however, requires troublesome manual operations, namely, firstly removing a lamp housing cover, and next setting a light source in each receptacle on the flange, in order to set light sources in the lamp housing.
Meanwhile, it is desirable to break the electrical connection between a power supply and the connector by opening the illumination switch before the light source setting operations. However, the light sources may inadvertently be set or removed when the illuminating switch is closed.